scholarly journals Devising a method to improve the accuracy of maintaining the pre-set temperature and humidity conditions at a vegetable storage facility under a food storing mode

2021 ◽  
Vol 2 (2 (110)) ◽  
pp. 89-98
Author(s):  
Petro Kachanov ◽  
Oleh Yevseienko ◽  
Nataliia Yevsina
Keyword(s):  
Transfer Functions ◽  
Control Object ◽  
Operation Time ◽  
Maximum Error ◽  
Insulation Material ◽  
Storage Facility ◽  
Position Controller ◽  
Controlling Elements ◽  
Energy Consuming ◽  
Product Storage

A vegetable storage facility is an energy-consuming object with distributed parameters. The quality of product storage depends on the microclimate in the vegetable storage facility: current temperature, humidity, and carbon dioxide level. Existing temperature controllers in a vegetable storage facility use a two-position law of control, which leads to the consumption of excess energy and product spoilage. The purpose of the study is to improve the work of the controller in the process of product storage at the storage phase due to closing the two-position controller through feedback in the form of a first-order aperiodic link. To achieve the goal, the procedure for calculating the transfer function of a control object through the equation of thermal balance was used. This procedure made it possible to take into consideration the parameters of a vegetable storage facility: the area and the type of thermal insulation material of floorings, the weight, and the type of a stored product, as well as thermal energy supplied to the vegetable storage facility. Based on the heat balance equation, the nature of the operation of controlling elements, transfer functions of a vegetable storage facility without a product, and the vegetable storage facility filled with a product, were calculated. The heat model of a vegetable storage facility was constructed in the MATLAB Simulink environment (USA) to check the algorithms of the temperature field control. The product storage for 180 days with changes in the daily temperature of outdoor air from minus 8 °C to plus 2 °C and changes in humidity from 50 % to 100 % was modeled. According to the results of modeling, it is possible to conclude that the addition of an aperiodic link to the feedback of the two-position controller will enable taking into consideration the inertia of a control object. This allows decreasing the maximum error in control of self-oscillations to 0.15 °C and decreasing the total operation time of controlling elements by 13 %

Noninvertible Digital Transfer Functions Arising From Minimum Phase Analog Process Models

1983 ◽  
Vol 105 (1) ◽  
pp. 46-48
Author(s):  
C. P. Neuman ◽  
R. L. Morris
Keyword(s):  
Discrete Time ◽  
Process Model ◽  
Transfer Functions ◽  
Process Models ◽  
Minimum Phase ◽  
Time Model ◽  
Position Controller ◽  
Adaptive Cancellation ◽  
Tool Position ◽  
Model Reference Adaptive

Current approaches to discrete model reference adaptive control (MRAC) [1–6] require the inverse of the discretized process model to achieve the desired model following. The objective of this paper is to illustrate that the step-invariant transformation of a minimum phase, physical analog process model (based upon a machine tool position controller) leads to a nonminimum phase discrete-time model and thus precludes the possibility of obtaining a stable inverse for the discrete-time process model. This example illustrates the shortcomings of applying discrete MRAC to higher-order processes and indicates the need for alternative MRAC approaches which do not require the adaptive cancellation of process zeros.

scholarly journals A two-stage calibration method for industrial robots with joint and drive flexibilities

2015 ◽  
Vol 6 (2) ◽  
pp. 191-201 ◽  
Author(s):  
M. Neubauer ◽  
H. Gattringer ◽  
A. Müller ◽  
A. Steinhauser ◽  
W. Höbarth
Keyword(s):  
Transfer Functions ◽  
Geometric Model ◽  
Maximum Error ◽  
Industrial Robots ◽  
Robot Calibration ◽  
Two Stage ◽  
End Effector ◽  
The Real ◽  
Frequency Responses ◽  
Real Robot

Abstract. Dealing with robot calibration the neglection of joint and drive flexibilities limit the achievable positioning accuracy significantly. This problem is addressed in this paper. A two stage procedure is presented where elastic deflections are considered for the calculation of the geometric parameters. In the first stage, the unknown stiffness and damping parameters are identified. To this end the model based transfer functions of the linearized system are fitted to captured frequency responses of the real robot. The real frequency responses are determined by exciting the system with periodic multisine signals in the motor torques. In the second stage, the identified elasticity parameters in combination with the measurements of the motor positions are used to compute the real robot pose. On the basis of the estimated pose the geometric calibration is performed and the error between the estimated end-effector position and the real position measured with an external sensor (laser-tracker) is minimized. In the geometric model, joint offsets, axes misalignment, length errors and gear backlash are considered and identified. Experimental results are presented, where a maximum end-effector error (accuracy) of 0.32 mm and for 90 % of the poses a maximum error of 0.23 mm was determined (Stäubli TX90L).

Gas Turbine High Temperature Casing Upgrade

2005 ◽  
Author(s):  
Alexei N. Orberg ◽  
Vladimir B. Soudarev
Keyword(s):  
High Temperature ◽  
Natural Gas ◽  
Gas Turbines ◽  
Operation Time ◽  
Insulation Material ◽  
Pumping Stations ◽  
Investigation Methods ◽  
Flow Investigation ◽  
Turbine Casing ◽  
Gas Pumping

Due to enormous material losses in the case of emergency, it is vital to ensure the operation reliability of the natural gas pipeline compressor stations (CS). The risk of breakdown is rather high for gas turbines (GT) with total operation time approaching the design-estimated life and particularly for those in which the actual period of operation exceeds this value. Over 25% of turbine drives working on natural gas transportation net in Russia have exceeded their design life [1]. For instance, around 600 gas turbines of the GTC-10-4 type (10MW power) are still in service despite their 120,000–160,000 hours of operation (more than 1,000 gas turbines GTC-10 type have been made and installed at natural gas pumping stations in the seventies in Russia). These gas turbines contain several critical components. Most of them are related to the high temperature parts, including inner high-temperature turbine casing (ITC). This ITC is a kind of a collector (duct) connecting a combustion chamber outlet and the turbine’s entry. Combined with an insulation layer, it serves as a protective shield for outer (main) turbine casing against the effect of hot gases. Notwithstanding the fact that the GTC-10-4 turbine has a modest inlet gas temperature (TIT∼800°C), there are various problems with the ITC shape and state during the turbine’s operation. The ITC operates under conditions of dramatic temperature changes, pressure drops, extended periods of high temperature. All these factors can cause the ITC shell deformations, which results in poor turbine performances. Regular maintenance inspections including opening a turbine do not permit to establish reasons for dramatic changes in the ITC shape. A detailed numerical analysis has been performed to better understand the ITC dynamics over its service period of operation. Moreover, it should be observed that ITC forms a flow prior to entering a turbine. Then, gas flow is directed to the first stage nozzles of the turbine. Advanced numerical flow investigation methods were applied to improve hot gas distribution in front of the turbine. A considerable decrease in velocity nonuniformity was achieved both radially and circumferentially through the ITC shape optimization. Great need in this component stimulated introduction of a new manufacturing technology aimed at production of new ITCs and replacement of numerous defective ones still used at natural gas pumping stations across Russia. Results of thermo-deformation analysis and numerical flow investigation for various ITC configurations are presented in the paper. It also contains proposals for improving the state of the ITC and outer turbine casing (OTC) in the result of the fixing unit development and applying a new insulation material.

Optimum external wall insulation thickness considering the annual CO2 emissions

2018 ◽  
Vol 42 (4) ◽  
pp. 527-544 ◽  
Author(s):  
Ioannis Axaopoulos ◽  
Petros Axaopoulos ◽  
John Gelegenis ◽  
Emmanouil D Fylladitakis
Keyword(s):  
Thermal Behavior ◽  
Transfer Functions ◽  
Residential Buildings ◽  
Climatic Data ◽  
Insulation Material ◽  
Cooling Period ◽  
Insulation Thickness ◽  
Optimization Methodology ◽  
The City ◽  
Optimum Insulation Thickness

Increasing the insulation thickness in residential buildings leads to the reduction of operational CO2 emissions but simultaneously increases the embodied CO2 due to the insulation material. The environmentally optimum insulation thickness exists at a point where the total CO2 emissions are minimum. This work presents the optimum insulation thickness for external walls of different composition and orientation, for both the heating and the cooling period. Three different wall types and insulation materials are being presented. The dynamic thermal behavior of the external walls simulation is based on the heat conduction transfer functions method and using the hourly climatic data available for the city of Athens, Greece. The optimization methodology uses a single objective function approach, combining the simulation of the thermal behavior of external walls with an optimization algorithm. The results indicate that the optimum insulation thickness varies from 11.2 to 23.4 cm and is different for each orientation, wall type, and insulation material. In addition, the total annual CO2 emissions per unit area of the wall can be reduced by 63.2%–72.2%, depending on the insulation material and its position on the wall.

scholarly journals A Mathematical Model for a Conceptual Design and Analyses of UAV Stabilization Systems

Fluids ◽  
2021 ◽  
Vol 6 (5) ◽  
pp. 172
Author(s):  
Vadim Kramar ◽  
Aleksey Kabanov ◽  
Sergey Dudnikov
Keyword(s):  
Mathematical Model ◽  
Transfer Functions ◽  
Mutual Influence ◽  
Complete System ◽  
Control Object ◽  
Stabilization System ◽  
Elastic Deformations ◽  
Dynamic Constraints ◽  
Control Actions ◽  
Analysis And Synthesis

This article considers the principle of constructing mathematical models of functionally complex multidimensional multiloop continuous–discrete UAV stabilization systems. This is based on the proposal for constructing a mathematical model based on the class of the considered complexity of the stabilization system-multidimensionality, multi-rating, and elasticity. Multiloop (multidimensional) UAV stabilization systems are often characterized by the control of several interconnected state elements and the existence of several channels for the propagation of signals and mutual connections between individual objects. This is due to the need not only to take into account the numerous disturbing factors (for example, wind) acting on the control object as well as the need to use several points of application of control actions. Additionally, an important point is the possible separation of the mutual influence of the roll and yaw channels of the UAV on its synthesis and analysis. For this purpose, a mathematical model has been constructed using a description in the form of transfer functions, and therefore, in the form of structural diagrams. The principle of obtaining transfer functions is shown to demonstrate additional dynamic constraints introduced by elastic deformations into the stabilization loop through gyroscopic devices and accelerometers. This will make it possible to formulate a methodology for analyzing the influence of aeroelastic constraints on the stabilization loop, which will allow developing approaches to formulate requirements for the effective placement of gyroscopes and accelerometers on the UAV. The proposed approach allows creating a complete system of analysis and synthesis tools for complex multidimensional continuous–discrete UAV stabilization systems.

scholarly journals An Optimum Structure of Scalable Capacitors in 3D Crosspoint Memory Technology

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2755
Author(s):  
Yuya Tone ◽  
Toru Tanzawa
Keyword(s):  
Maximum Error ◽  
The Other ◽  
Cmos Process ◽  
Insulation Material ◽  
Optimum Structure ◽  
Model Accuracy ◽  
Capacitance Density ◽  
Contour Plots ◽  
Metal Wires ◽  
Good Agreement

Memory chips need large capacitors in their periphery to drive boosted word-lines and bit-lines for read and write operations. In a previous work, scalable capacitors were proposed for 3D crosspoint memory to keep the area for the capacitors constant over technology generations. This paper proposes the capacitance models of three types of wiring capacitors: (1) vertical capacitor, (2) vertical and horizontal capacitor with next-neighbor wires connected with the other terminal, and (3) vertical and horizontal capacitor with next-neighbor pairs connected with the other terminal. These models are based on Wong’s crossover capacitor model to determine the capacitor structure with the highest capacitance density in 3D crosspoint memory technology. One can determine the best structure through optimizing the process parameters such as the height H of the insulation material between the metal wires and the thickness T of the metal wires and the design rules such as the width W and space S of metal wires. The model accuracy was in good agreement with the measurement of twelve types of capacitor structures fabricated in a 180 nm 6 metal standard CMOS process with the maximum error of 20%. Contour plots of the capacitance density across H vs. S where it is assumed that W = T = S are shown. As a result, the boundary condition regarding H and S is determined per 3D crosspoint memory technology with three, four, or five levels of wires.

scholarly journals Boiler drum automatic power management system

2020 ◽  
Vol 222 ◽  
pp. 01009
Author(s):  
Tatiana Efremova ◽  
Sergey Shchegolev
Keyword(s):  
Automatic Control ◽  
Transfer Functions ◽  
Dynamic Properties ◽  
Block Diagram ◽  
Control Object ◽  
Feed Water ◽  
Boiler Drum ◽  
Action Models ◽  
Working Out ◽  
Feed Water Temperature

Dynamic properties of boiler sections as control objects are studied. The requirements for mathematical models and the main adjustable parameters in drum boilers are determined, on the basis of which the requirements for the designed model are made. The construction of a block diagram and calculation of transfer functions of the automatic control system of the control object. The main types of disturbances are determined: feed water and steam consumption, consumer load, fuel consumption, and feed water temperature. Each perturbation is represented as a control action. Models of the object using perturbation channels are obtained. The article considers the construction of an effective model of the system of automatic control of the drum boiler power supply based on the system’s working out of disturbing influences. The paper uses the Matlab application software and the Simulink graphical programming environment.

Time Study of Automatic Edgebanding Machine Using BP Artificial Network

2012 ◽  
Vol 430-432 ◽  
pp. 1514-1518
Author(s):  
Jing Xin Hao ◽  
Wen Jin Liu
Keyword(s):  
Mean Squared Error ◽  
Operation Time ◽  
Good Method ◽  
Maximum Error ◽  
Detailed Data ◽  
Bp Network ◽  
Simulation Accuracy ◽  
Target Error ◽  
Squared Error ◽  
Artificial Network

The edgebanding time is measured in one furniture factory made for wardrobe in Guangdong province, the BP network model has been built between operation time and length of gluing edge, cross edge, thickness of edgeband, then the data is calculated, trained and simulated by BP network tool box of Matlab R2009b.The result shows that BP network is a good method to build the correlation between factors and operation time, and the simulation accuracy is high by training of detailed data, MSE(Mean Squared Error) fulfills the target error of 0.001 when the net training get 1470 cycles, and the maximum error of output is less than 0.3 second, the relative error was less than 5%, the actual requirement of practice can be fulfilled.

Automation of Concrete Heat Treatment in Thermoactive Formwork in Monolithic Housing Construction

2020 ◽  
Vol 897 ◽  
pp. 250-254
Author(s):  
Anatoly Fedorovich Tikhonov
Keyword(s):  
Heat Treatment ◽  
Mathematical Model ◽  
Control System ◽  
Transfer Functions ◽  
Block Diagram ◽  
Control Object ◽  
Housing Construction ◽  
Control Actions ◽  
Concrete Mix ◽  
Concrete Temperature

The block diagram and algorithm for concrete treating in thermoactive formwork is presented. Article presents parameters of the concrete mix, to enter in a command block before automated heating of the concrete mix in thermoactive formwork in accordance with the schedule of changes in concrete temperature in the process of obtaining desired strength. Article formulates mathematical model of the control object for thermal treatment of concrete with consideration of the specifics and general patterns, processes and technological requirements. Article determined control actions, transfer functions of the object and phase graph of the control system.

scholarly journals Research on Non-Contact and Non-Fixed Cable Force Measurement Based on Smartphone

2021 ◽  
Vol 11 (19) ◽  
pp. 8902
Author(s):  
Yongwei Wang ◽  
Kunyao Li ◽  
Yuan Chen ◽  
Shuyuan Xu ◽  
Wenchi Shou
Keyword(s):  
Force Measurement ◽  
Real Life ◽  
Operation Time ◽  
Maximum Error ◽  
Video Data ◽  
Stay Cable ◽  
Vibration Displacement ◽  
Cable Force ◽  
Cable Force Measurement ◽  
Cable Forces

Stay cable is the major load-carrying element in cable-stayed bridges. The process of monitoring cable forces would be beneficial to ensure the safety of bridges. The conventional sensor-based approaches to measure stay cable forces is complicated in operation, time-consuming and relatively expensive. In order to confront these disadvantages, a lightweight measurement method using smartphone imagery was proposed in this paper. The video data acquisition process was first standardized by using a pre-designed target. Then, a novel algorithm to extract the vibration displacement of stay cables under complex condition was developed. An automatic correction algorithm was provided to further improve the displacement results. On top of that, a smartphone-based software for determining cable forces was developed and tested on a real-life bridge. The results showed a maximum error of 1.99% compared with the cable force obtained by using a dynamic tester. The developed software is proven to be feasible in real-life projects and can achieve high accuracy in cable force determination. At the same time, the proposed method does not require a fixed camera for measurement and is not limited by personnel experience and measurement time, facilitating real-time monitoring of multiple projects, multiple cable surfaces and multiple personnel in a visual vibration environment.

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